Variable speed drive for bicycles and the like

ABSTRACT

A variable speed &#34;stiff-hub &#34; drive adapted particularly to bicycles and comprised of a constant mesh infinitely variable gearing with an integral input crank shaft projecting axially from opposite ends of an enclosing case, with a drive sprocket at one side of the case and coaxially disposed over one of said crank shaft ends, and having a control means which operates in conjunction with a single lever which also comprises the braking force actuator.

This is a continuation of application Ser. No. 428,029, filed Dec. 26,1973, entitled Vehicle Transmission and Brake now abandoned.

BACKGROUND

It is a general object of this invention to provide vehiculartransportation capable of moving varied loads at varied speeds and undervaried conditions, utilizing a prime mover having capabilities thatrequire mechanical advantage, particularly when human powers are reliedupon. Although the concepts herein disclosed are applicable to engine ormotor powered vehicles and/or like devices, it is the human poweredvehicle and/or device such as a bicycle in which this invention isadvantageously embodied as hereinafter disclosed. Working pressureavailable from human power is substantial while continued musculareffort through the movement of human limbs is limited, and thereforeefficient mechanical advantage is much to be desired, and it is to theseends that I have provided this improved and cooperatively relatedvehicle, transmission and braking.

Referring to the motivating power necessary to accelerate and to propelbicycles and the like, especially human powered vehicles, a multi-speedtransmission is commonly employed, but limited to certain spaced gearratios. Derailleur chain and sprocket gearing is commonly employed, andthere are geared hubs, for implementing speed ratio changes between thefoot pedal operated crank and the supporting drive wheel. The commonlyaccepted type of gear changer is the Derailleur type, with its speedratio limitations and complexities which not only encumber the vehiclebut which are vulnerable to damage. Therefore, it is an object of thisinvention to eliminate gear ratio limitations and to provide infinitelyvariable gear ratios within the range required. With the presentinvention, a variable ratio transmission is provided for changing theangular velocity from an input shaft to an output shaft; and in theparticular case illustrated, to increase angular velocity from a bicyclecrank shaft to a drive sprocket that rotates a drive wheel (the rearwheel).

Variable ratio transmissions of the prior art have not been positive,and in one way or another rely upon frictional engagement between thedrive and driven members; reference being made to cone or V-belt pulleydrives, disc and roller drives. Also, variable ratio transmissions existin the form of both hydraulic and electric apparatus wherein currentflow is controlling, but not absolutely positive in every application.On the contrary, meshed gear engagement is positive and it is thereforean object of this invention to provide positive in-mesh infinitelyvariable ratio transmission of rotative power having the advantages ofdirect and positive gear engagement between an input shaft and an outputshaft. With the present invention, there is a constant mesh ratiochanger and variable speed feedback to an element thereof adding to orsubtracting from the output velocity, and in the preferred embodimentthere are first and second stages of gearing and there is a variablespeed feedback into one stage to add or substract angular velocity asmay be required. A feature of the transmission is the feedback throughnon-reversible gearing which substantially reduces the torquerequirement of the infinitely variable speed control means that governsthe input-output speed ratio.

Transmissions involving gears and controls therefor are most oftenweighty and space consuming, it being an object of this invention toprovide a variable ratio transmission of the character thus far referredto that is small and compact, and consequently of relatively lightweight. The bicycle, for which the embodiment herein disclosed isdesigned, is a light weight competition cycle, in which case the inputtorque on the crank shaft is quite high. Therefore, it is also an objectto provide a durable gearing that will withstand any and all mechanicalpressures likely to be imposed thereon. In practice, the first andsecond gearing stages are of the planetary type with multiple pinionshaving wide faced toothed engagement, while the speed regulating controlmeans includes a non-reversible worm and wheel feedback drive into thesecond stage gearing operating at lower torque value than the firststage gearing. Anti-friction bearings are used exclusively in thejournaling of all torque transmitting and/or higher velocity elements.

The independent controllability of prior art bicycle transmissions andbraking has involved separate manual controls, the former requiringselective positioning and the latter requiring forceful actuation. It isan object of this invention to combine the independent controllabilityof these two control functions into one control means by which bothselective positioning and forceful actuation are manually applied. Aswill be described, the controlling means comprises a lever havingdistinct modes of actuation, one whereby it is rotatively positioned toeffect selectivity of the variable output ratio of the transmissionhereinabove referred to, and one whereby it is forcibly displaced toeffect actuation of the brake.

The usual hanger assembly of the conventional bicycle is replaced in thepresent invention, it being an object to provide a frame adapted toaccept the transmission of the character hereinabove referred to. Inpractice, the said transmission and its control means are combined in acasing adapted to be disassembled for accessibility, and for removal andreplacement.

DRAWINGS

The various objects and features of this invention will be fullyunderstood from the following detailed description of the typicalpreferred form and application thereof, throughout which descriptionreference is made to the accompanying drawings, in which:

FIG. 1 is a side elevation of the vehicle transmission and brake of thepresent invention.

FIG. 2 is an enlarged detailed sectional view of the transmission takenas indicated by line 2--2 on FIG. 1.

FIGS. 3, 4, and 5 are sectional views taken as indicated by lines 3--3,4--4, and 5--5 on FIG. 2.

FIG. 6 is a sectional view of the variable speed feedback drive whichcharacterizes the present invention, being a view taken as indicated byline 6--6 on FIG. 3.

FIG. 7 is an enlarged fragmentary and sectioned view of the singlecontrol means (removed from FIG. 1) provided for braking and tocondition the transmission.

FIG. 8 is a sectional view taken as indicated by line 8--8 on FIG. 7.

PREFERRED EMBODIMENT

The present invention involves, generally, a vehicle X and transmissionY and brake concept cooperatively combined as a bicycle adapted to bepowered by a rider for motivation. The prerequisites of a highperformance bicycle are light weight, strength, and a wide transmissionrange; and it is in each of these that the present invention providesimprovements. Firstly, the constant mesh infinitely variable speedtransmission Y is characterized by a casing of a type and configurationunprecedented in cycle frames, and in this respect the vehicle X isprovided with a frame for the replaceable combining of said transmissionY therewith. Secondly, the variable speed controllability of thetransmission Y is effected by control means C that simultaneouslycontrols the independent actuation of the brake.

TRANSMISSION-FRAME

The vehicle X involves a frame to which the case of the transmission Yis removeably and/or replaceably secured. As will be hereinafterdescribed, the transmission Y involves several interrelated gear meansand a variable speed feedback, in which case there is a sizeable gearcase 10 disposed on a transverse horizontal axis on which the crankshaft 11 projects therethrough to carry a pair of diametric crank arms12 at its opposite projecting ends. There are pedals 13 at the workingends of the arms for conventional application of force by a rider. Theinterior of case 10 is to accommodate the said several gear means, therebeing carrier bearings 14 and 15 at axially opposite ends of the case tocarry the crank shaft 11 through members telescopically engagedthereover; one end of the case being permanently closed by a wall 16 andthe other end by a removeable plate 17. The carrier bearings 14 and 15are journaled in the wall 16 and plate 17 respectively. The interior ofthe case 10 is open radially for the accessible installation of thevariable feedback, and over which there is a removeable cover 18. Inpractice, the variable feedback and its cover 18 are horizontallydisposed to project forwardly, the cover 18 being detachably secured tothe case housing 19 by means of a screw fastener 20.

In accordance with this invention, the case 10 hereinabove described isfastened into the frame of the vehicle X so that the one structurallycomplements the other. Although the frame type or configuration canvary, the preferred "diamond" frame is employed as shown, involving acenter post 21, a head 22, upper and lower rails 23 and 24 extendingbetween the upper and lower extremities of the post and headrespectively, and convergent lower and rear forks 25 and 26 extendingrearwardly from the bottom and top extremities of the center postrespectively. The joinder of the bottom and lower extremities of thepost 21, lower rail 24 and lower fork 25 is by means of a saddle 27having a seat complementary to the exterior of housing 19 of thetransmission case 10. In practice, the seat is an arcuate quadrantcentered about the axis a of the crank shaft 11, there being widelyspaced and parallel flanges 28 embracing the opposite faces of thesaddle and fastened thereto by screw fasteners 29 in shear, as isclearly shown. Correspondingly, each of the frame elements 21, 24 and 25are comprised of monocoque tubes and by joinder at the head 22 and byjoinder into the saddle 27. The member which comprises the saddle 27 areof shell-form and become monocoque when secured into working position asby heli-arc welding.

CONTROL

The vehicle X involves a single control means C for governing the gearratio of the transmission Y and for applying actuation force to thebrake. As shown, the bicycle has a front fork 31 comprised of a headerwith an upstanding tube 33 and spaced depending tubes 34 on which thefront wheel 35 is journaled upon an anti-friction hub 36. The upstandingtube 33 is journaled within the head 22 by means of spaced anti-frictionbearings, the tube 33 projecting upwardly to carry a transverse handlebar 32 affixed thereto as shown. The front wheel has a tyred rim 37 thatrevolves forwardly beneath the header 33, and it is in this area of thebicycle structure that the front brake is installed. Also, the bicyclehas the rear forks 26 on which the rear wheel 28 is journaled upon ananti-friction hub 39. The rear wheel has a tyred rim 37 that revolvesforwardly within the upper extremity of forks 26, and it is in this areaof the bicycle structure that the rear brake is installed.

TRANSMISSION

The single control means C for the vehicle X governs the gear ratio ofthe transmission Y for applying propelling force to the rear wheel 28.The transmission Y is uniquely a constant mesh infinitely variable speedtransmission adapted in this instance to bicycle requirements whereinthere is a high torque low velocity input and a low torque high velocityoutput and involves the case 10 mounted to the saddle 27 and in whichthe crank shaft 11 is journaled upon the bearings 14 and 15 as abovedescribed. The oppositely projecting crank shaft 11 is revolved byopposite end crank arms 12 at high torque and low velocity, and there isa drive sprocket 51 coaxially rotatable over the shaft 11 and exposed atthe exterior of the case 10 to transport a chain 52 that extends to adriven sprocket 53 affixed to the hub of the rear wheel 28. The drivesprocket 51 operates at infinitely variable angular velocity andcorresponding variable torque, as compared with the input shaft 11; itbeing understood that said shaft 11 is operable at varied speeds andwith the application of different torque values.

In accordance with this invention, the transmission Y comprises aconstant mesh speed changer B and a variable speed feedback means F. Thespeed changer B is comprised of an input gear 55, an output gear 56, anda feedback gear 57. The output gear 56 is characteristically a planetgear that cycles around the input sun gear 55 and within the feedbackring gear 57, or the equivalent gearing. The variable speed feedback Fis a means that governs the angular velocity of the feedback gear 57 andis characteristically a non-reversible gear engagement and theintermeshed engagement of all gear teeth is constant, the variable speedfeedback velocity being applied in relation to the output velocity andcontrolled so as to determine the velocity of the output gear 56. Incarrying out this invention, the non-reversible gear engagement of thevariable speed feedback F to the feedback gear 57 of the speed changer Ais a worm and wheel engagement, wherein the worm gear 58 is operated atinfinitely variable speed in governing the angular velocity of the wormwheel 59, and controlling the angular velocity of gear 57 connectedtherewith so that the input-output velocities are accordingly added toor subtracted from as may be required.

In accordance with this invention, the transmission Y comprises firstand second stages of gearing with a consequent substantial reduction oftorque requirement on the variable speed feedback F. As shown, the firststage gearing involves a speed changer A and the second stage gearinginvolves the speed changer B. Like the speed changer B, speed changer Ais comprised of an input gear 65, an output gear 66, and a stationaryring gear 67. The input gear 65 is characteristically a planet gear thatcycles around the output sun gear 66 and within the ring gear 67, or theequivalent gearing. In the case illustrated where torque reduction is tobe established at the feedback gear 57, the primary ratio of gear changeis obtained by step-up gearing in stage A and step-down gearing in stageB. For example, the ring gear 67 is three diameters of the output gear66, in which case the step-up ratio is 4 to 1 with a correspondingreduction in torque; while the ring gear 57 is two diameters of inputgear 55, in which case the step-down ratio is 3 to 1 with acorrespondingly further reduction in torque and with the result thatreduced force is required to control the angular velocity of the wormwheel 59 which drives the same at varied speeds. The 4 to 1 velocityincrease will be divided by three when the ring gear 57 is stationary.

However, when the ring gear 57 is revolved with and at a velocity equalto that of the output gear 56, there is no reduction in the primary 4 to1 ratio. The worm gear 58 of feedback F can be employed to propel theworm wheel 59 and feedback gear 57 at any angular velocity slower orfaster than that of the input gear 55, thereby to subtract or add to theoutput ratio of output gear 66 relative to input gear 55.

In carrying out this invention, the input planet gears 65 of speedchanger A are journaled on bearing trunnions 60 disposed in acircumferential series projecting inwardly from a drive flange 61 onshaft 11 inward of and seated against the carrier bearing 14. The ringgear 67 is fixedly captured in the housing of case 10 by the plate 17,there being a retainer ring 62 embracing the trunnions 60 to hold thegears 65 in place. The output gear 66 of the first stage gearing iscoupled directly to and preferably integral with the input gear 55 ofthe second stage gearing, these two gears being concentrically journaledby a common tubular hub over shaft 11 by needle bearings 63. The outputplanet gears 56 of speed changer B are journaled on bearing trunnions 64disposed in a circumferential series projecting from a drive flange 68on tubular drive shaft 69 journaled on needle bearings 70 upon shaft 11,there being a retainer ring 71 embracing the trunnions 64 to hold thegears 55 in place. The shaft 69 extends to the exterior of the housingwall 16, being seated against carrier bearing 15 to driveably supportthe drive sprocket 51 at the exterior of case 10. The feedback gear 57is then journaled over the shaft 11 and tubular shaft 69 by means of aconcentric hub 72 disposed between flange 68 and the bearing 15. Inpractice, needle bearings are employed therebetween and an anti-frictionaxial thrust bearing 73 disposed against a drive gear 74 for means Fprojecting radially from the bearing 15 used as a positioning stoptherefor. As will be apparent from the drawings, the aforementionedtransmission elements are assembled into case 10 from the ends thereofand captured in working position by the plate 17 and a snap ring 75respectively.

ROTATIONAL FEEDBACK

In accordance with this invention, the variable speed feedback means Fis provided to govern the angular velocity of the controlling feedbackgear 57. As shown, the gear 57 is integral with the worm wheel 59, andthe means F governs the angular velocity of worm gear 58 that isconstantly meshed therewith. In practice, I employ a high velocityvariable speed drive driven by the output velocity of the second stagegearing B and driving the worm wheel 59 through worm gear 58. Varioustypes of variable speed drives can be employed, the most practical ofwhich is a frictional drive as shown. Accordingly, the feedback means Finvolves drive cone 75, a driving cone 76, a belt 77 operabletherebetween, and a positioning means 78 for operational placement ofsaid belt. The drive cone 75 is driven by drive gear 74, while thedriving cone 76 drives the worm wheel 59.

The housing 19 of the transmission case 10 is provided with one or moreopenings to pass the drive and driving elements of the drive cone 75 anddriving cone 76, said cones being journaled on spaced and parallelshafts 80 and 81 extending laterally of the case in a plane normal tothe housing of said case. The shafts 80 and 81 are carried byanti-friction ball bearings to extend between the side wall of thehousing 19 and a header 82 spaced therefrom by a post 83 disposedintermediate the two cones. A drive gear 74 is fixed to drive shaft 80within the housing 19 and is a bevel gear constantly meshed with thegear 74, to have a speed increase of 1 to 5. A driving gear 84 is fixedto driving shaft 81 within the housing 19 and turns a feedback shaft 85through a speed increasing gear 86. Although the driving of worm gear 58can be direct from driving shaft 81, a speed increase of 1 to 2 isdesired in the embodiment shown, wherein the worm to wheel ratio is 20to 1 (a non-reversible ratio).

Referring now to the variable function of the cones 75 and 76, they areinversely tapered cones between which the belt 77 frictionally transmitsangular velocity dependent upon the radius of engagement. Assuming theengaged radii of the two cones to be the same, the belt 77 will transmitequal angular velocity through both. However, as the engaged radius ofone is increased and the other decreased, the angular velocity of thelatter is increased relative to the former, and vice versa. In theembodiment shown, the drive cone is larger than the driving cone,proportioned to operate the latter between a speed reduction of 11/2 to1 to a speed increase of 1 to 2. The positioning means 78 foroperational placement of the belt 77 is shown as a fork 87 embracing thedrive cone and having spaced fingers 88 projecting inwardly from eachleg of the fork to guide the oppositely running portions of the belt.Fork 87 is pivoted at its top end, so that its free swinging ends movebetween the two cones. In practice, a return spring 89 retracts the freeend of the fork toward the speed increasing ends of the cones while apull cable 90 extending to the control means C is fixed thereto to drawthe free ends of the fork toward the speed decreasing ends of the cones.The cover 18 attached to post 83 encloses the feedback means F andsupports the anchor and guide 92 for the pull cable 90. It will be seenthat the angular velocity of the feedback shaft 85 varies infinitelyaccording to placement of the belt 77 by frictionally engaging theinversely tapered cones.

BRAKE-TRANSMISSION CONTROL

Referring now to the control means C for applying the brakes and forconditioning the ratio determining element of the transmission feedbackmeans F, the control means C is a handle 100 that is manually operableto simultaneously actuate the brakes and condition the transmission;being compressible to effect the former and rotatable to effect thelatter. The handle 100 is carried by the handle bar 32 to depend fromthe conventional grip portion 101 of said handle bar, there being a base102 attached to the grip by a clamp 103 so as to project laterally ofand preferably forwardly from the handle bar and its conventional (race)configuration; downwardly and rearwardly turned. A feature of thecontrol means is the swivel 104 disposed on the laterally extended axisof the base and to which the handle 100 is pivoted by a transverse pin105. The handle 100 is a first class lever having a pull pin 106 spacedfrom pivot pin 105 and to which the actuation cable 50 of brake Z isaffixed for movement through a sheath seated in the swivel; the usualmanner of pulling such a brake cable. The swivel 104 is rotatablycaptured to the base 102 by a center shaft 107, there being a frictionwasher 108 disposed between the swivel and base, and a spring washer 109cpatured by a nut so as to apply pressure thereto. It will be observedthat the base 102 and swivel 104 are tubular and telescopically relatedfor rotatable stability, there being a tangential opening 110 throughthe base with a seat for the sheath of pull cable 90. Accordingly, thereis a peripheral channel 111 in the swivel 104, and aligned with theopening 110, to accommodate the pull cable 90 as it extends to an anchorpoint within the swivel. Thus, the swivel draws in the cable as it isturned counter clockwise (as shown) and lets out the cable as it isturned clockwise, the former to increase speed of the feedback means Fand the latter to decrease the same. It will be seen that independentcontrol of the brakes and transmission Y is effected with the controlmeans C, while the bicycle rider has but the one control member to beconcerned with, and such that the braking function is ever present whenthe gear ratio changes are to be made.

Having described only a typical preferred form and application of myinvention, I do not wish to be limited or restricted to the specificdetails herein set forth, but wish to reserve to myself anymodifications or variations that may appear to those skilled in the art.

I claim:
 1. A low velocity high torque infinitely variable speedconstant mesh transmission for bicycles and the like, including; a casewith a crank shaft extending therethrough and with its opposite endsprojecting from the case, a first stage speed changer comprising, astationary ring gear and an input planet gear journaled on a carrierdriven by the crank shaft and in constant mesh with said ring gear, andan output sun gear in constant mesh with said planet gear to be drivenat increased angular velocity thereby; and a second stage speed changercomprising, an input sun gear driven by the first stage sun gear and aplanet gear journaled on an output carrier rotatable over the crankshaft and in constant mesh with said second stage sun gear, and arotatable ring gear in constant mesh with said planet gear; and aninfinitely variable speed feedback drive means driven by the outputcarrier of the second stage and controlling the angular velocity of therotatable second stage ring gear to effect a commensurate velocitychange between the crank shaft and the output carrier.
 2. The two-stageinfinitely variable speed constant mesh transmission as set forth inclaim 1 wherein the feedback drive means is a non-reversible gearengagement with the second stage ring gear.
 3. The two-stage infinitelyvariable speed constant mesh transmission as set forth in claim 1,wherein the infinitely variable feedback is a high velocity driverotating the second stage ring gear to reduce velocity in said secondstage speed changer.
 4. The two-stage infinitely variable speed constantmesh transmission as set forth in claim 1, wherein the infinitelyvariable feedback comprises inversely tapered cones with an axiallypositioned belt engaged therebetween, one cone driven by the outputcarrier of the second stage speed changer and the other cone driving therotatable ring gear of the second stage speed changer.
 5. The two-stageinfinitely variable speed constant mesh transmission as set forth inclaim 1, wherein the infinitely variable feedback comprises inverselytapered cones with an axially positioned belt engaged therebetween, onecone driven by the output carrier of the second stage speed changer andthe other cone driving the rotatable ring gear of the second stage speedchanger through a non-reversible worm and wheel drive.
 6. The two-stageinfinitely variable speed constant mesh transmission as set forth inclaim 1, wherein the case has spaced end walls with carrier bearingsthrough which the crank shaft projects with oppositely exposed ends. 7.The two-stage infinitely variable speed constant mesh transmission asset forth in claim 1, wherein the case has spaced end walls with carrierbearings through which the crank shaft and second stage carrier extendoutside the case with the opposite ends of the crank shaft driveablyexposed.
 8. The two-stage infinitely variable speed constant meshtransmission as set forth in claim 1, wherein the case has spaced endwalls with carrier bearings through which the crank shaft and secondstage carrier extend outside the case with a drive sprocket exposed onthe carrier and with opposite ends of the crank shaft driveably exposed.9. The two-stage infinitely variable speed constant mesh transmission asset forth in claim 1, wherein the infinitely variable feed comprises aright angle gear driven from the second stage carrier and on an axisparallel to feed back gearing into the second stage ring gear.
 10. Thetwo-stage infinitely variable speed constant mesh transmission as setforth in claim 1, wherein the infinitely variable feedback comprisesinversely tapered cones journaled on spaced parallel axes disposednormal to the crank shaft axis, an axially positioned belt engagedbetween the cones, one cone driven by the output carrier of the secondstage speed changer and the other cone driving the rotatable ring gearof the second stage speed changer.
 11. The two-stage infinitely variablespeed constant mesh transmission as set forth in claim 1, wherein theinfinitely variable feedback comprises inversely tapered cones journaledon spaced parallel axes disposed normal to the crank shaft axis, anaxially positioned belt engaged between the cones, one cone driven bythe output carrier of the second stage speed changer and the other conedriving the rotatable ring gear of the second stage speed changerthrough a non-reversible worm and wheel drive.